Quentin Coldwater probably wasn't expecting much more from his day than an entrance interview to Princeton and an awful lot of boredom and amateur magic tricks, with perhaps a few daydreams about the world of Fillory, a magical kingdom from the books he read as a child. However, things take a turn for the strange when his interviewer turns up dead, and one of the paramedics at the scene decides to hand over some of the deceased's belongings to Quentin; this leads him quite abruptly onto the grounds of the Wizarding School Brakebills, which, after an especially arduous examination, accepts him as a student. After five long years at Brakebills, our hero drifts in Manhattan as a fully-fledged magician with far too much time on his hands... up until he discovers that Fillory, the world he always dreamed of visiting, is very real- and within reach.

The sequel, The Magician King, focuses on Quentin as king of Fillory along with three characters from the previous book, and on a quest he undertakes for seemingly no reason other than to defeat his own ennui, but quickly turns into something a great deal more serious. This is alternated with the story of Julia's own path of magic after parting ways with Quentin, intersecting at various points with the plot of the first novel.

A third novel, The Magician's Land, is set to be published sometime in 2013-2014.

Bigger on the Inside: Many magical buildings are larger on the inside, such as the cottage that the Physical Kids hang out in.

Bittersweet Ending: Alice is dead, Quentin is traumatized, and Fillory is no better than the real world...but it seems there may be hope, for Quentin personally and for Fillory's national future, when Quentin and his friends decide to return and take the throne.

Ditto for the second book: Quentin is left behind as dryad Julia and his friends descend into the unknown. And on top of all that, he gets kicked out of Fillory by Ember, Fillory's resident god/guardian.

Deconstruction: Can be seen as a deconstruction of the Harry Potter series, in that it explores the realities of what an elitist magical academy might be like, as well as the effects on our protagonist, Quentin. At some points it also manages to make magic seem well, magical again, for example when Professor Myakovsky reverses entropy as a class demonstration, or Quentin's first piece of magic. Quentin can also be seen as a deconstruction of the sort of person who wishes he could enter a fantasy world, given that he ends up dissatisfied with just about everywhere he goes- to the point that Alice eventually calls him on it.

The realm of Fillory may also be a deconstruction of Narnia, or at least the idea of a magical world to escape to, as it is pointed out repeatedly that their world is not a plaything.

Julia also fits this in the second book, though her route is outside of the magical mainstream.

Developing Doomed Characters: The first half of the first book is about the titular Magicians' time in magic school. While interesting in it's own right, and important in that it sets up the characters, who are very well developed and realistically drawn, the plot doesn't really pick up motion until Penny shows up with the Button. Also, as a whole the group isn't exactly overflowing with the most admirable or heroic qualities.

Did You Just Punch Out Cthulhu?: "It's a funny thing about the old gods. You think that just because they're old, they must be difficult to kill. But when the fighting starts, they go down just like anybody else. They're not stronger, they're just older."

Double Standard Rape (Divine on Mortal) Brutally subverted when Julia offers herself to Reynard the Fox to save her friends. She meant she offered to die in their place... he interpreted it in a different way.

The Big Guy: Josh (large in size, and capable of extremely powerful magic...when he actually manages to cast a spell that is)

The Chick: Quentin (oblivious to any possible negative tension within the group, the only one to really believe in magic according to Alice)

Freudian Excuse: We learn that Martin Chatwin was molested as a child--by the future author of the Fillory series--and only entered Fillory in an attempt to escape.

Functional Magic: Magic is highly technical and rules-based. Magicians cast spells by saying a string of words (many of them in obscure, dead languages) and performing a set of complex Magical Gestures. New magicians must also memorize huge books full of Circumstances that change how a spell works, from the phase of the moon to the weather.

Possibly justified, on the grounds that Jane Chatwin was only given the time-travel watch because of Martin's rise to power in Fillory. Therefore, the range of universes she could create would be limited to ones in which Martin went to Fillory and made it possible for her to time travel in the first place. If this analysis is correct, it would effectively be a case of Stephen Hawking's "cosmic censor" stepping in to prevent a Grandfather Paradox from arising.

Hufflepuff House: There are many other schools of magic. Only one student from one of them appears more than once.

Similarly, the other Disciplines of magic: the only one formally introduced is Physical Magic. The others- Nature, Illusion, Healing, Psychic, Knowledge, etc- are only given a few fleeting but tantalizing references.

Humanoid Abomination: The Beast (a.k.a. Martin Chatwin) is at first believed to an extension of something even worse investigating our dimension. It's actually a human that spent too much time in Fillory. Not that that's any better.

Magic A Is Magic A: Magic seems to follow it's own internal rules, some of which the protagonists and magical society at large seem to know, and some that they don't, for example the "turtles all the way down" speech Quentin and his friends get at the start of their first class. But if you know the spell you're using and the Circumstances where you are,and preform the spell correctly then you'll get a predictable result- the Circumstances are so idiosyncratic that the students have to basically be imprisoned in Antarctica for a term repeating spells until they internalise some of the "grammar" of magic.

Magic Misfire: Casting advanced spells when upset will generally result in the caster transforming into a creature of pure magic, with lethal results (both for the caster and for anyone in the way).

Magicians Are Wizards: Quentin accidentally does real magic while peforming sleight-of-hand coin tricks, which is what initially attracts the attention of Brakebills. It is also mentioned that some hedge wizards make a living as stage magicians.

Magic Versus Science: Quentin and his friends are urged at the beginning to think of their studies as a purely practical course with a minimum of theory. Apparently many magicians have tried and failed to unearth the roots of magic. But they do have an understanding of the Circumstances, Alice and Penny manage to cobble together offensive spells from books, and in a conversation Alice says that spells demonstrably pull energy from the enviroment to work, though how or at what distance isn't specified. The Physical discipline of magic, which Quentin and his friends are in, specialises in messy practical magic that is based off of Physics. So it's unclear how much understanding they have,but it seems like a lot of work was done to get that understanding and work is still being done to expand it, and it's mentioned that some of the new magical research being done involves using recent scientific discoveries. Science Is Wrong is averted, it's more that figuring out magic seems to be a lot harder than gravity.

Make a Wish: When Quentin finds the Questing Beast, he is granted three wishes, though there are apparently limits to what he can wish for.

Master of Illusion: The discipline of Illusion Magic is all about this. Though only addressed in passing, the Brakebills Illusionists are skilled enough to make sure that nobody really knows where they gather.

Masquerade: The school's mysterious nature is hidden by magic, as are many other magical locations.

The sequel adds a second masquerade of hedge witches and various fair folk that the Brakebills magicians don't know about.

Muggles: Most people simply don't have the particular aptitude for magic: either they're not intelligent enough, they don't have the capacity for spellcasting, or they simply weren't able to pass the entrance exam. Although a childhood crush of Quentin's fails the exam for Brakebills, she becomes a hedge witch

One-Hour Work Week: Magicians that leave the magical world tend to find employment in businesses that are enchanted to diguise the fact that none of them actually do anything. Emily Greenstreet is one of these types, as is Quentin at the end of the novel--before his friends invite him back to Fillory.

One-Winged Angel: Alice's transformation into a niffin: "Do you think you're the biggest monster in the room?" A rare example of this trope in that a) it's used by a good guy, and b) it actually wins the fight.

This Loser Is You: Do you enjoy escapist fantasy? Ever long for adventure, magic, and whimsy? Then you must have a lot of issues--in fact you might just be a depressive malcontent at odds with just about anywhere you end up--at least if you're similar to the protagonist of this book.

Took a Level In Badass: Quentin, when we he walks naked to the South Pole. He levels up again after he studies magic by himself in the Centaur monastery. Also Alice, when she fights Martin Chatwin. At the end of the book, Eliot, Janet and Julia appear to have levelled up dramatically too.

Two Guys and a Girl: The initial setup with Quentin, Julia, and James. Quentin, Alice, and Penny may be considered this trope as well.

The sequel has examples of:

Ascended to A Higher Plane of Existence: At the end of the book Bingle, Abigail the sloth, and Julia journey to the flip side of Fillory, and as yet to be created world, which is said to be an improved upon version of Fillory, in the same way that Fillory is an improved upon version of Earth.

Nay Theist: The Free Trade Beowulf group and the Order, who both regard gods as magicians who use a more potent but not fundamentally different form of magic. The former group even tries to gain access to the gods' magic, with catastrophic results.

The Old Gods: Referred to by name. They've found out about the magic leak, and they're out to fix it.

Our Dragons Are Different: The Dragon of The Grand Canal. Quentin explicitly mentions that he finds it disappointing that not all dragons are the fire-breathing marauding type, and that fantasy books set him up for disappointment.

Sufficiently Analyzed Magic: The method of teaching magic fits this to a T. The analysis is so single-minded that only the most intelligent and obsessed candidates can even manifest the simplest magic consistently.

Talking Weapon: One of the competitors in Quentin's tournament is an intelligent sword.

Took a Level In Badass: Despite being more or less ineffective in the fight scenes of the previous book, Quentin absolutely demolishes any opposition put in front of him.

Julia, the hedge-witch, has become more powerful in many many ways than the Brakesbills kids, and over the course of the book we learn how she leveled up and by the end she's taken the ultimate power up by becoming a demi-goddess

Also Josh, to a lesser extent. He's set himself up in Venice as The Fixer, a go-between between the "official" magical world and the underground. He's also noted to have become more confident in his magic and we learn has been through some intense shit himself.

Two Lines, No Waiting: Alternates between the present day following Quentin and what happened to Julia during the first book; the two plots mirror each other.

This work mentions and references:

Narnia: The basis of the magical world of Fillory. Though the real Fillory (and all the counterpart characters) turn out to be a Nightmare Fuel-eriffic, cynical, worst-case-scenario version of a Narnia-type setting.

Harry Potter: Jason mentions Quidditch, and there are other small allusions throughout.

Lord of the Rings: Josh wants to see if he can find Middle Earth at the end of the first book.

Traveller: The name of the group Free Trader Beowulf (and the text of their recruiting pitch) are direct references to a famous Classic Traveller scenario--THE introductory adventure for many players in the early 80s once it became clear to GDW that their worldbuilding was as much of a draw as their ruleset.